Quiz - Physics - Displacement

[BlueTrin]

PQNLD? That's kind of the point. And yes, if I'd grown up with/worked with SI I'd be happier in that. I've worked in SI for four years of undergrad plus ~5 years of work life and it's still a bit "abstract" to me.

I wanted to make sure I understood.

It will always be abstract for you because you don’t use it in daily life.

You can be familiar with the conversions but it does not mean much until you have to use SI units for daily life ... for example for groceries, going to the butcher, ..,

 

[JohnN]

I wanted to make sure I understood.

It will always be abstract for you because you don’t use it in daily life.

You can be familiar with the conversions but it does not mean much until you have to use SI units for daily life ... for example for groceries, going to the butcher, ..,

And cooking. . . . . wait. . . . you still use teaspoons and tablespoons

 

[BlueTrin]

And cooking. . . . . wait. . . . you still use teaspoons and tablespoons

Well I live in the UK but I am French.

However I don’t think the tablespoon and teaspoon are used as real units in the UK. I think they are used as approximate units in cookbooks: i.e. just use a spoon to measure it ...

 

[skearse]

I wanted to make sure I understood.

It will always be abstract for you because you don’t use it in daily life.

You can be familiar with the conversions but it does not mean much until you have to use SI units for daily life ... for example for groceries, going to the butcher, ..,

Exactly. The original supposition was that imperial units are a "serious PITA" (meh-maybe) and "[have] no merit." My point being that for about 327 million of us, along with the population of the two other countries that still use them, they do have merit.

 

[BlueTrin]

Exactly. The original supposition was that imperial units are a "serious PITA" (meh-maybe) and "[have] no merit." My point being that for about 327 million of us, along with the population of the two other countries that still use them, they do have merit.

Yes I agree it would take a long time to get used to any change.

 

[Angelo Farina]

This sounds like a law that is doing a serious disservice to the students. In the days of a global economy, having an awareness of multiple unit systems makes one a more capable scientist/engineer. That's not to say that non-SI units are superior, but an awareness that the world beyond the borders of Europe exists.

In fact a typical exam test has a mixture of wrong and correct SI units, and the student has to convert immediately all the input data to SI and perform all the calculations and write the results in SI units. If he keeps the wrong units, he is rejected even if the calculations are correct!

 

[rhwestfall]

Interesting enough, I grew up in the "must go metric" era of the 1970's here in the USA. It fizzled.... Fast forward about 15 years ago, the State Department of Transportation here in NY went 100% metric for all projects (must be designed as such, not converted). Then about 4 or 5 year ago, went back to imperial...

The eternal ebb and flow....

 

[Angelo Farina]

kp is a kilopond. It's essentially the same as a kgf. Common use unit prior to the SI adaptation of the newton in the 1960s and still gets used in certain circles today.

Not to be confused with a kip.

I truly never heard of a "kilopond". Here when I was a student we did use kgf (kilogram-force), as SI became mandatory by law in 1981, and so for most of my school and university a number of professors were using the old units.
In 1981 everything changed. I graduated in 1982, and so I had to write my Master Degree Thesis in SI units, after having studied for 18 years with the other system. It was not easy. But everyone had to do this change in 1981...
Despite this, no one ever called a kgf a "kilopond". Probably this term was used only in some country.
Nowadays the usage of kgf is almost a crime here in Italy, you risk fines and disciplinary actions.
But what most worries an engineer, is that if you use not-SI units in your technical documents, and then some accident occurs, you are automatically hold responsible of the failure, and you can risk jail if there were injuries or deaths. This even if the calculations were correct, as for the judge a formal error is much more severe than a technical error, and cannot be mitigated.
So we teach our students about the importance of always employing correct SI units, because not doing so exposes them to severe professional, civil and penal risks.

 

[Vitesse2l]

UK building trades are still mostly imperial.

Few years ago I was ordering some 1/2" metal bar from our supplier so asked for 12.7mm diameter (we usually ordered in metric) only to be told they stocked 13mm, plus or minus a manufacturing tolerance. I received 1/2" bar. We were happy to work in metric or imperial but I could never get my head around dimensions with tolerances expressed as +/- 1/64". Thou of an inch was my preference and didn't need converting before measuring.

 

[Angelo Farina]

Yes I agree it would take a long time to get used to any change.

We had to change in just one year, in 1981. It was hard, but in the end it solved a number of problems...
We had to discard all the old manuals and buy new books for everything, all converted to SI units.
Consider that in Italy, before SI, we had THREE unit systems: Giorgi (MKS), which is quite close to SI, CGS and the technical engineering system (the one using kgf, called ST, Sistema Tecnico).
In Physics we did use Giorgi (MKS), in Chemicals we did use CGS, and in Engineering sciences the third one (ST).
So it was really a mess, and SI was a benediction, solving all the problems!